Wood grinder



P. PRIEM woon GRINDER April 29, `1924.

s sheets-sheet 2 Filed Feb. 24 1923 INVENTOR Fnufp PR/Em ATTORNEYS April29, 1924; 1,492,389

P. PRIEM wooD GRINDER Filed Feb. 24, 1923 5 Sheets-Sheet 3 Ff@- 5fAlNvENToR Pflug. Pfr/EM.'

v BY

ATTORNEYS 40 chain 14 running over one of the Patented Apr. 29, @924.

UNITED STATES 1,492,389 PATENT oEFicE.

PAUL Param, or HEIDENHEIM, GERMANY, AssrcNoa 'ro MEEICAN vorrir coN'racrCOMPANY, INC., or NEW YoEx, N. Y., A conronArIoN or NEW YoEx.

WOOD GRINDER.

Application tiled February 24,1923. Serial No. 621,117.

To all whom it mag/'concerm Be it known that I, PAUL PRTEM, a citizen ofthe Republic of Wurtemberg, Germany, residing at Heidenheim on derBrenz,

Germany, have invented certain new and.

matically iegulatin t-he pressure against the grind stonentha-t t elatter may be driven vat a substantially constant load and speed.

This regulation isaccoinplished according to the invention, throughmeans responsive to the varying demand on the driving motor to maintainthe stone at constant speed.

The underlying thought is susceptible of embodiment in various forms ofequipment,

some of which are illustrated in the accompanying drawings, in which-Fig. 1 is a more or less diagrammatic broken side elevation of a woodgrinder installation in which my invention is embodied in one form; andl Figs. 2, 3 l4 and 5 are similar views of different embodiments of theinvention.

Referring to Fig. 1, I have indicated at 5 an electric motor of constantspeed type,

s0 which drives the grind stone' 6 through any suitable operatingconnection, such as a belt lor chain 7. Associated with the grind stoneis a series of press lungers 8, each working in its independent eedchamber 9 to force a charge of wood blocks 10 a ainst the stone. Each ofthe plungers is f forward by a pinion 11 engagin the rack 12 on the stemof the lunger an driven throu h a chain connection 13, which in turn isriven b a sproc et wheels 15. The chain 14 is driven from the pinion 16on the shaft of a worm wheel 17,

with which meshes the worm 18 on the spindle 19 of a press feedmotor 2Oof the 46 variable speed type. Current is led to the ress feed motor 20through a rheostat 21, aving a series of contacts'22 over which travelsan arm 23, pivoted at 24 and counter-weighted at 25. i lSecured to thelever23 5o is the movable core 26 of a solenoid winding 27 amnged in thecircuit 28 of the stonedriving motor 5.'

It is obvious that if. the load on the grindV stone 6 varies, incidentto the character of` u the wood billets l10 which are forced againstlrheostat v21 arranged in the circuit of the ,the stone by the presses,a variation of current in-put to the grind-stone drive motor 5 results,since the stone is driven at constant speed. The consequent variation inthe current flow through the solenoid winding 27, influences theposition of the solenoid core 26. This displacement of the solenoidshifts the contact arm 23 across the rheostat contacts 22, and a greateror less resistance is thus interposed in the circuit of the ress feedmotor 20. As a consequence, the rive of the press plungers 8 isaccelerated or retarded, and the load on the stone is thus automaticallymaintained substantially constant. The speed of the stone is thus alsomaintained substantially constant.

A modified arrangement in which the same result is accomplished isillustrated in Fi 2, in which the drive of the stone 6 throug the beltor chain 7 is taken from the turbine 29.` The driving belt 7 o crates acentrifugal governor 30, to a col ar 31 of which is connected one arm ofthe Contact arm 32 which ,travels over Lthe contacts 22 of the feedmotor 20 for the ress. The latter is here indicated as of differenttype. Thus the feed motor spindle 19 is provided with two worms 33 and34, which meshwith worm wheels 35 and 36 on the shafts 37 and 38 of thegears which drive the press chains 39 and 40. The latter are arranged ato posite sides of the hop er 41 and engage t e opposite sides of thecliarge of wood blocks 42 and feed the latter against the vstone 6.

The operation of this installation is analogous to that first described.When the frictional drag of the wood blocks on the grind stone variesythe speed of the turbine 29 and the governor 30 is corres ondin lyaffected. The contact arm 32 is t us shifted up or down on the contactsof the rheostat 21 and the current suppl to lthe press feed motor 20 isincreased or ecreased, thus acceleratin or retarding the feed chains 39and 40. Tiie load on the stone is thus maintained substantiallyconstant, and a drive of the stone at substantially uniform speedattained. f

In the construction shown in Fi 3 the arent of the press and its eedmotor 20 is substantially identical with that just -described The grindstone 6, however, is

.driving fluid or gas crank shaft 44 of a reciprocating engine 45 whichmay be of an suitable type. The mitted to or exhausted fromy thecylinders of the engine 45 may be led through a pipe 46 to which opens abranch 47 leading to the pressure box 48. Working within the latter is aspring-opposed piston 49the stem 50 of which is connected to one arm ofthe contact lever 51 which travels over the contacts 22 of the rheostat21 arranged in the circuit of the feed motor 20. As the load on thestone 6 varies, the pressure head of the or fluid admitted to or fromthe cylin ers of the driving'A engine 45 varies, and this variation iscommunicated to the pressure box 48 throu h the branch 47. The piston 49is there ore shifted in one direction or the other, and correspondinglyshifts the position of the contact lever 51 on the rheoetat 21. Thespeed of the feed motor 20 is thus controlled. Y

Still another embodiment of my invention is illustrated in Fig. 4, inwhich the drive of the stone 6 is similar to that shown in Fig. 1. Thepress lungers 8 are also of the type shown in i0. 1, but the drive ofthe gear 17, instead ofe being taken from an electric motor 20, istaken, in this modification, through a belt or chain 52 passing around adriving pulley or r 53 on the shaft 54 of a turbine 55. T e gas or fluidwhich drives the turbine 55 enters through the` ipe 56 in which isarranged a valve 57, t e stem 58 of which is connected to the solenoidcore 59, which, as in-Fig. 1, is hung from one end of an arm 60 pivotedat 61 and counter-weighted at 62. The winding 63 of the solenoid isarranged inthe circuitof the stone-driving motor 5.

The operation is also analogous to those above described. As the load onthe stone varies, with consequent variation in the current in-put to themotor 5, the solenoid core 59 rises and falls, and thus varies theposition of the valve 57 which controls the flow to the press-feedturbine 55. The feed of the press is thus altered, and the drive of thestone at substantially constant speed is secured. v

A further embodiment of m invention is illustrated in Fi 5, in whic thestone 6 is driven, as in igs. 1 and 4, from a constantl speed electricmotor. The press is of the type shown in Figs. 2 and 3, com

prising feed chains 39 and 40 operated through gears 35 and 36 and worms33 and 34 on a spindle 19. The latter, however, is driven according tothe present modification from a rotary pump 64 operating as a fluidmotor. This pump, preferably of y the toothed wheel type, drives thepulley 65,

on which runs the chainor belt 66 to the pulley 67 on .a gear shafttransmitti motion to the bevel gear 68 at one' end 1,4.ea,see

the worm'shaft 19.l '111e Huid which drives the rotary pump 64 isdelivered thereto from a second pump 69 of the same or different type,the pulley 70 for operating which is driven from the constant speedelectric motor 5 through a chain or belt 71, although the pump may bedriven from a se arate source of power. The iiuid upon which the pump 69operates is contained in a tank 72 and 1s delivered by the pump 69 topiping 73, through which it passes to the motor pump 64 to actuate thelatter which discharges the fluid again to the tank 72.

Arranged in the piping 73 is a control valve 57, the stem 58 of which isconnected to the cone 59 of the solenoid winding 63 arranged inthecircuit of the motor 5.v As in the construction shown in Fig. 4, thesolenoid is attached at its upper end to the lever 60 pivoted at 61 andcounterweighted at 62. i As above explained, the current demand of theconstant speed motor 5 varies with the load imposed upon the stone 6 bythe feed chains 39 and 40. The fluctuation of current varies theposition of the solenoid core 59'and thus alters the position of thevalve 57 so that more or less duid is delivered by the pump 69 to thepump 64 which operates the feed chains and thus varies the load upon thegrind stone 6 in accordance with the current demand upon the motor 5.

Various other embodiments of m invention will readily occur to thosedealing with the problem, without departing from what I claim as myinvention.

I claim- 1. In a wood grinder installation, a grind stone, a motor fordriving the same,.a pre for mechanically feeding a charge of wood blocksagainst the stone, a variable feed rotary motor for advancing the re,and means responsive to the wer emand on the stone-driving motor or relating the e'ort of the variable spee press-feed motor to maintain thepre load on the stone substantially constant.

2. In a wood grinder installation, a grind stone, a motor for drivingthe same, a press for mechanically feeding a charge of wood blocksagainst the stone, a variable feed rotary motor for advanacing' thepress, a membermovable with and subject to fluctuations in the powersupply to the driving motor incidental to the drive of the stone atconstant spleed, and means operatively associated wit said movablemember for regulating the. power in-put to the variable speed press-feedmotor to maintain the press load on the stone subdantially constant.

j 3. In a wood grinder installation, a grind stone, a motor for drivingthe same, a pres for mechanically feedinga char of wood blocks againstthe stone, a gear for advancing the rees, a variable speed electro-motorfor driving the feed ar, and means for controlling the'speed o thevariable speed electro-motr to maintain sub- 5 stantially constant theload on the grind stone.

4. In a wood grinder installation, a grind stone, a motor for drivingthe same, a press for continuously feeding a charge of wood f blocksagainst the stone, a feed gear for ad r 10 vancing the ress, a variablespeed electro motor for driving the feed gear, and means for controllingthe speed of the variable `speed electro motor to maintain substantial`ly constant the load on the grind stone. 15 In testimony whereof I havesigned my name to this specification.

PAUL PRIEM.

